1. Field of the Invention
This invention relates to metalurgy, and more particularly to iron and steel recovery from scrap metal.
2. Description of the Prior Art
At the time an automobile is no longer a means of conveyance, or a source of spare parts, it becomes a disposal problem. Automobile graveyards are becoming more prevalent and the government has expressed an interest in removing this "pollution problem".
The junked automobile carcasses would have an application in steelmaking process if a low cost method could be found to remove the residual alloy content of copper, nickel, chromium, lead, zinc and aluminum to leave a low residual alloy steel feed for, primarily, electric furnaces.
Some prior art is known. Senior et al, in U.S. Pat. No. 3,206,299, discloses a conventional low grade ore reducing kiln process which includes a pretreatment step of oxidizing for purposes of dehydration and removal of volatiles. This is followed by, generally, standard reduction process techniques.
Rhinehart, in U.S. Pat. No. 4,014,681, discloses an energy recycling process to be used with automobile scrap. In the Rhinehart process, a totally stripped vehicle body--that is, one stripped of alternators, radiators, generators, starters, voltage regulators, transmissions, carburetors, glass, etc.--is moved by conveyor into a cupola where it is melted. Carbon electrodes are required to generate the necessary 3,200 degree F. temperature. The thrust of this patent is the use of heat generated in recycling to, for example, preheat the charge. The charge is drawn off molten, in layers if possible.
Evans et al, in U.S. Pat. No. 4,200,262, discloses a method and apparatus for removing combustible material from metal scrap. Evans characterizes his apparatus as a rotating retort and its use is for burning combustibles such as oil from scrap metal such as turnings, chips, shearings, punchings, and other similar materials which tend to include a coating of oil which must be removed before reclaiming. In the Evans apparatus, temperatures of 50 to 500 degrees F. are used in an oxidizing atmosphere through which the material moves, conveyed forward by the rotating retort.
None of these references deal with a high alloy scrap which removes the alloys in a non-molten atmosphere. None will accomodate an entire vehicle, bumper, tires, etc. and many prior art solutions are totally non-economical because of high energy demands of the process as would be needed for the high temperatures utilized in, for example, Rhinehart.